H04L29/00—Arrangements, apparatus, circuits or systems, not covered by a single one of groups H04L1/00 - H04L27/00 contains provisionally no documents

H04L29/12—Arrangements, apparatus, circuits or systems, not covered by a single one of groups H04L1/00 - H04L27/00 contains provisionally no documents characterised by the data terminal contains provisionally no documents